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JOHN A. THOMP'SONOF AUBURN, NE`W`YORK.

Letters Patent No. 79,030, dated t'tmc 16, 1868.

IMPROVEMENT IN MACHINE EQR GRINDING MOWING-MAGEINE KNIVES.

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TO ALL WHOM IT MAY CONCERN:.

Be it known that I, JOHN A. THOMPSON, of Auburn, in the county of Cayuga, `and State of New York, have invented certain new and useful Improvements in Machine for Grinding Harvester-Cutters; and I do hereby declare that the following is a; full, clear,.aud exact description thereof, reference being had to the accompanying drawings, making'part of .thisfspecilieatiom and to the'letters of reference marked thereon, like letters indicating like parte Wherever they occur.

To enable -others skillcdin the art to construct and use my inventjonI will proceed to describe it.

My present-invention consists incertain improvements in the machine patented to me, March 17, 1868, and relates to certain details in the construction and means for adjusting the same. i l

Figure 1 is a perspective view, and Y Figure 2 a modification of thelsame.

Figures 3, 4, and 5 are details ofthe same.

Figure 7 is a. top plan `view, and

Figure 8 is atransverse section' of a modification ot my apparatus.`

Inthis, as in my former machine, I clamp the sickle toa bar, C, to hold it while being ground. In the face of this bar C, I form a groove, to receive the bar of the sickle, as shown by a, fig. 4, this groove being deep enough to permit the projecting heads of rivets or bolts on the sickle to slide in'without' touching. i i To 'secure the sickle in position I use clamping-bolts, K,having their ends turnedy at right angle, and provided with rollers, J, vwhich may also be` grooved, to permit the heads of rivets to pass without hitting. On the face of the bar C, I also secure a series of rollers, L, for the back of the sickle to rest on, as represented in fig. 5. This bar C, thus constructed, islconnected to another bar, C', by means of a metallic guide-plate, A, which is pivoted to the bar, and is provided with eurved slots, B, as represented in iig. `.1", the 'rear end of this plate'A working in guides,-V, on a similar plate, D, secured to a block, pivoted to a sliding baseby a clamp'- bolt, asrshown in g. 1. The bars C and C are further connected by a couple ot' elbow-levers, b, as represented.

p To the plate A, a lever, E,Ais pivoted VatI, and to this is pivoted a link, I',- the oppositeV end ofthe latter being pivoted to the plate D, so that by operating the lever E, the bar C, with the sickle attached, is moved forward or back, as may be desired. Or, if preferred, the plate D may bedispensed with, and thie plate A made long enough to reach back and rest upon a curved bar, H, attached to the rear bar (las shown in iig. 1,

to whichit may be clamped, as represented in g.` 3.

yIt is obvious, however, that the same movements and adjustments may b'e accomplished by a still simpler form ofthe device,l as shown in iig. 7. In this ease the bar C, to which the sickle 'is secured, is clamped vdirectly to the bar C, and arranged to slide longitudinally thereon, there being either a dove-tailed or V-shaped groove in the face of one of the bars, to receive and guide a corresponding part on the otherv bar, as: shown in iig. 8. In this I conhectthe elbow-levers I1 both at the same point, at the centre of bar C', and pivot their rear end at a common centre on an index-plate, A, secured to the block D, theindex-plate A, in this case, havinga groove or slot extending half way around, as shown in g. 7, Vby which a much greater inclination may be given tothe parts than When'construeted Vas in iig. 1. In this case the lever E is pivoted, by means of cars, to the centre of the plate A, and thelink E', by similar ears, to a stud,- m, which latter serves to connect the elbow i levers l to `the bar C', by being made tubular, and secured-bye. bolt, O, as shown in iig. 8.

The plate Ais provided with a similar stud, upon which the rear ends of the links Z are'pivoted, .and which is clamped to the'block t by a bolt, e, in the same manner.

By this arrangement of the parts it will be seen that the machine is very much simplified, and that it is also rendered capable of a very wide range of adjustments.

By operating the lever E, the bars C and C are shoved forward or thrown back, as may be desired.

For more conveniently using the apparatus, I providea grindstone, P, With a shaft extending at each end, and having a smaller stone, R, arranged so as to be adjusted on either end of the shaft, for the purpose of grinding the teeth at or near the extreme end of the sickle.

vacca 2 Having thus described my invention, what I claim is j 1. Providing the bar C with the rollersL, and the clamps Kprovided Awith therollers J, substantially as described.

A In combination with the bars C and Cf, connected by the jointed links b, I claim vthe plates A and D, constructed and arranged to operate as set forth.

- 3. The bar C', connectedv to the index-plate A by the jointed links b; and the lever-s E and E2 substantially as represented in gs.;7 and 8. j

4. In combination with'the apparatus, constructed as'last above described, I claim arrangngthe bar C' to slide longitudinally thereon, for the purpose Vof moving the sickle along without changing the position of `the frame, as set forth.

5. The auxilia'iystone It, when arranged to be adjusted on either endof the shaft, for use in connection with the main stone I?, substantially as and for the purpose set forth.

' F JOHN A. THOMPSON.

' Witnesses:

Emu. BROWN,

C.- Bnsfron, 

